// <numbers> -*- C++ -*-

// Copyright (C) 2019-2020 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file include/numbers
 *  This is a Standard C++ Library header.
 */

#ifndef _GLIBCXX_NUMBERS
#define _GLIBCXX_NUMBERS 1

#pragma GCC system_header

#if __cplusplus > 201703L

#include <type_traits>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

/** @defgroup math_constants Mathematical constants
 *  @ingroup numerics
 *  @{
 */

/// Namespace for mathematical constants
namespace numbers
{
#define __cpp_lib_math_constants 201907L

  /// @cond undoc
  template<typename _Tp>
    using _Enable_if_floating = enable_if_t<is_floating_point_v<_Tp>, _Tp>;
  /// @endcond

  /// e
  template<typename _Tp>
    inline constexpr _Tp e_v
      = _Enable_if_floating<_Tp>(2.718281828459045235360287471352662498L);

  /// log_2 e
  template<typename _Tp>
    inline constexpr _Tp log2e_v
      = _Enable_if_floating<_Tp>(1.442695040888963407359924681001892137L);

  /// log_10 e
  template<typename _Tp>
    inline constexpr _Tp log10e_v
      = _Enable_if_floating<_Tp>(0.434294481903251827651128918916605082L);

  /// pi
  template<typename _Tp>
    inline constexpr _Tp pi_v
      = _Enable_if_floating<_Tp>(3.141592653589793238462643383279502884L);

  /// 1/pi
  template<typename _Tp>
    inline constexpr _Tp inv_pi_v
      = _Enable_if_floating<_Tp>(0.318309886183790671537767526745028724L);

  /// 1/sqrt(pi)
  template<typename _Tp>
    inline constexpr _Tp inv_sqrtpi_v
      = _Enable_if_floating<_Tp>(0.564189583547756286948079451560772586L);

  /// log_e 2
  template<typename _Tp>
    inline constexpr _Tp ln2_v
      = _Enable_if_floating<_Tp>(0.693147180559945309417232121458176568L);

  /// log_e 10
  template<typename _Tp>
    inline constexpr _Tp ln10_v
      = _Enable_if_floating<_Tp>(2.302585092994045684017991454684364208L);

  /// sqrt(2)
  template<typename _Tp>
    inline constexpr _Tp sqrt2_v
      = _Enable_if_floating<_Tp>(1.414213562373095048801688724209698079L);

  /// sqrt(3)
  template<typename _Tp>
    inline constexpr _Tp sqrt3_v
      = _Enable_if_floating<_Tp>(1.732050807568877293527446341505872367L);

  /// 1/sqrt(3)
  template<typename _Tp>
    inline constexpr _Tp inv_sqrt3_v
      = _Enable_if_floating<_Tp>(0.577350269189625764509148780501957456L);

  /// The Euler-Mascheroni constant
  template<typename _Tp>
    inline constexpr _Tp egamma_v
      = _Enable_if_floating<_Tp>(0.577215664901532860606512090082402431L);

  /// The golden ratio, (1+sqrt(5))/2
  template<typename _Tp>
    inline constexpr _Tp phi_v
      = _Enable_if_floating<_Tp>(1.618033988749894848204586834365638118L);

  inline constexpr double e = e_v<double>;
  inline constexpr double log2e = log2e_v<double>;
  inline constexpr double log10e = log10e_v<double>;
  inline constexpr double pi = pi_v<double>;
  inline constexpr double inv_pi = inv_pi_v<double>;
  inline constexpr double inv_sqrtpi = inv_sqrtpi_v<double>;
  inline constexpr double ln2 = ln2_v<double>;
  inline constexpr double ln10 = ln10_v<double>;
  inline constexpr double sqrt2 = sqrt2_v<double>;
  inline constexpr double sqrt3 = sqrt3_v<double>;
  inline constexpr double inv_sqrt3 = inv_sqrt3_v<double>;
  inline constexpr double egamma = egamma_v<double>;
  inline constexpr double phi = phi_v<double>;

#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_FLOAT128)
  template<>
    inline constexpr __float128 e_v<__float128>
      = 2.718281828459045235360287471352662498Q;

  /// log_2 e
  template<>
    inline constexpr __float128 log2e_v<__float128>
      = 1.442695040888963407359924681001892137Q;

  /// log_10 e
  template<>
    inline constexpr __float128 log10e_v<__float128>
      = 0.434294481903251827651128918916605082Q;

  /// pi
  template<>
    inline constexpr __float128 pi_v<__float128>
      = 3.141592653589793238462643383279502884Q;

  /// 1/pi
  template<>
    inline constexpr __float128 inv_pi_v<__float128>
      = 0.318309886183790671537767526745028724Q;

  /// 1/sqrt(pi)
  template<>
    inline constexpr __float128 inv_sqrtpi_v<__float128>
      = 0.564189583547756286948079451560772586Q;

  /// log_e 2
  template<>
    inline constexpr __float128 ln2_v<__float128>
      = 0.693147180559945309417232121458176568Q;

  /// log_e 10
  template<>
    inline constexpr __float128 ln10_v<__float128>
      = 2.302585092994045684017991454684364208Q;

  /// sqrt(2)
  template<>
    inline constexpr __float128 sqrt2_v<__float128>
      = 1.414213562373095048801688724209698079Q;

  /// sqrt(3)
  template<>
    inline constexpr __float128 sqrt3_v<__float128>
      = 1.732050807568877293527446341505872367Q;

  /// 1/sqrt(3)
  template<>
    inline constexpr __float128 inv_sqrt3_v<__float128>
      = 0.577350269189625764509148780501957456Q;

  /// The Euler-Mascheroni constant
  template<>
    inline constexpr __float128 egamma_v<__float128>
      = 0.577215664901532860606512090082402431Q;

  /// The golden ratio, (1+sqrt(5))/2
  template<>
    inline constexpr __float128 phi_v<__float128>
      = 1.618033988749894848204586834365638118Q;
#endif // USE_FLOAT128

} // namespace numbers
/// @}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif // C++20
#endif // _GLIBCXX_NUMBERS
